A cylinder-direct injection engine has an injector which injects a fuel directly into a cylinder of the engine.
In the engine of this type, there is an interference period which is a range of a crank angle at which a part of the fuel injected from the injector is adhered to an opened intake valve. When an injection period, that is, a period during which the fuel is injected from the injector overlaps with the interference period, the fuel injected from the injector is adhered to the intake valve. As a result, a necessary amount of fuel cannot be supplied into the cylinder, which may cause a deterioration of emission and a reduction in an engine output. For that reason, for example, JP-A-2007-291887 discloses the injection period is changed and corrected to avoid the interference period.
Generally, in an engine, it is conceivable that an open/close period and a lift quantity of an intake valve are varied from an initial state due to abrasion or aging of the valve mechanism. Also, it is conceivable that an injection direction of fuel from the injector is deviated from the initial direction due to a variation in shape of an injection port of the injector or a variation in mounting angle of the injector.
For that reason, it is conceivable that the interference period is shifted with time. However, in a cylinder-direct injection engine shown in JP-A-2007-291887, it is assumed that the interference period is fixed. Even when the injection period is changed and corrected, the injected fuel may be adhered to the intake valve.